1. Technical Field
The present invention relates to a power transmission control device, a power transmission device, an electronic apparatus, and a load state detection circuit.
2. Related Art
In recent years, the spotlight has been on contactless power transmission (non-contact power transmission) that can transmit power using electromagnetic induction without using a metallic contact. The applications of such contactless power transmission technology include charging of cell phones and household appliances (e.g., handsets). Related-art examples of contactless power transmission technology include JP-A-2006-230032.
Unfortunately, in this related-art example, only a signal from one terminal of the primary coil is monitored when detecting the phase. This causes a problem that when there occurs an environmental variation, such as a voltage variation, an ambient-temperature variation, or a variation in the positional relation between the primary coil and secondary coil, the setting values, such as a threshold voltage to be used when detecting the phase, must be changed.